Shoe upper skin film for preventing dye migration

ABSTRACT

The present invention provides a shoe upper skin film for preventing dye migration, which comprises: a polyurethane skin or thermoplastic polyurethane (TPU) film having a color layer; and a thermoplastic polyurethane hot-melt film, wherein a film made of an ethylene-vinyl alcohol copolymer is formed between the TPU film and the hot melt film. Thus, when the skin film is bonded to a fabric, the dye of the fabric can be prevented from migrating to the skin film so that the color layer of the skin film can be stained from being stained.

REFERENCE TO RELATED APPLICATIONS

This is a continuation of pending International Patent Application PCT/KR2015/011990 filed on Nov. 9, 2015, which designates the United States and claims priority of Korean Patent Application No. 10-2015-0147917 filed on Oct. 23, 2015, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a shoe upper skin film for preventing dye migration, and more particularly to a shoe upper skin film for preventing dye migration, which can not only prevent the dye in a fabric from migrating to the skin film having a color layer when the skin film is bonded to the fabric by a conventional heat press operation, thereby preventing the skin film from being stained, but also prevent the color of the fabric from migrating to the skin film, even when the shoe is used for a long period of time.

BACKGROUND OF THE INVENTION

As is well known, in the shoe industry field, a method of manufacturing shoe uppers using hot-melt films without sewing (called ‘No Sewing’) is widely used, and various materials for decoration of shoe uppers have recently been used.

In recent years, skin materials made of polyvinyl chloride-based or polyurethane-based resins have been bonded to fabrics and have frequently been used as shoe uppers. For example, a technology of bonding a polyurethane-based film to a fabric for shoe upper material by a high-frequency bonding method after printing the top layer of the polyurethane-based film by a comma coater method, a screen printing method or a transfer method.

As described above, in the conventional method, the shoe uppers are manufactured using the ‘no sewing’ process. As shown in FIG. 1, the shoe uppers are mostly made of a skin film 10 having an at least two-layer structure, which is based on a hot-melt film 30 made of thermoplastic polyurethane and is obtained by coating a colored polyurethane skin thereon or coextruding a colored thermoplastic polyurethane film (hereinafter referred to as TUP film 20).

In order to use this skin film 10 as a shoe upper, the skin film 10 is placed on a fabric to be bonded and is subjected to a conventional heat press operation so that the thermoplastic polyurethane hot-melt film 30 forming the bottom of the skin film 10 can be melted and bonded to the fabric 40 by heat and pressure. In the heat press operation, the colored TPU film 20 coated on the hot-melt film 30 is not melted so that it can function as a material capable of decorating the shoe upper.

The conventional shoe upper skin film 10 configured as described above can undergo a dye migration phenomenon in which the color of the fabric 30 migrates to the skin film 10. Specifically, as shown in FIG. 2, when the skin film 10 is bonded to the fabric 40 by the ‘no sewing’ process, the dye migration phenomenon occurs in which a dye (red dye in FIG. 2) used to stain the fabric 40 migrates to the skin film 10 during the heat press operation, thereby changing the color of the skin film 10 (changing the color to an orange color in FIG. 2). For this reason, the skin film 10 cannot be used when it has a bright color. Furthermore, there are many limitations in choosing the color of the skin film. In addition, a problem arises in that when the shoe is worn for a long period of time, the color of the fabric 40 migrates to the skin film 10 so that the shoe cannot be aesthetically pleasing.

SUMMARY OF THE INVENTION

The present invention has been made in order to solve the above-described problems occurring in the prior art, and an object of the present invention is to provide a shoe upper skin film for preventing dye migration, which can prevent the dye in a fabric from migrating to a skin film when the skin film is bonded to the fabric.

A shoe upper skin film for preventing dye migration according to the present invention comprises: a hot-melt film; a dye migration-preventing film made of an ethylene-vinyl alcohol copolymer resin and formed on the hot-melt film; and a thermoplastic polyurethane film formed on the dye migration-preventing film.

Furthermore, a shoe upper skin film for preventing dye migration according to the present invention comprises: a dye migration-preventing hot-melt film made by processing a mixture of a thermoplastic polyurethane and an ethylene-vinyl alcohol copolymer; and a thermoplastic polyurethane film formed on the dye migration-preventing hot-melt film.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a figure showing the configuration of a shoe upper skin film according to a conventional art.

FIG. 2 is a figure showing a state in which the color layer of a TPU film was stained, because the dye in a fabric migrated to a TPU film when the skin film shown in FIG. 1 was bonded to the fabric.

FIG. 3 is a figure showing the configuration of a shoe upper skin film for preventing dye migration according to a preferred embodiment of the present invention.

FIG. 4 is a figure showing the configuration of a shoe upper skin film for preventing dye migration according to another preferred embodiment of the present invention.

FIG. 5 is a figure showing a state in which the color layer of a TPU film is clean, because the dye in a fabric did not migrate to the TPU film when the skin film shown in FIG. 3 was bonded to the fabric.

DESCRIPTION OF MAIN REFERENCE NUMERALS OF THE DRAWINGS

-   -   100 and 500: skin film; 200: TPU film;     -   300: dye migration-preventing film; 400: hot-melt film;     -   600: dye migration-preventing hot-melt film; 40: fabric.

DETAILED DESCRIPTION OF THE INVENTION

A shoe upper skin film for preventing dye migration according to the present invention comprises: a hot-melt film; a dye migration-preventing film formed on the hot-melt film and made of an ethylene-vinyl alcohol copolymer resin; and a polyurethane film formed on the dye migration-preventing film.

However, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, representative embodiments of the present invention will be proposed in order to achieve the above-described object. In addition, other embodiments of the present invention will become apparent from the following description of the present invention.

As used herein, the term “skin film” or “shoe upper skin film” means a skin material which is used as a shoe upper. Specifically, the term means a film made by bonding a thermoplastic polyurethane film or a polyurethane film to a conventional fabric so as to form a shoe upper. Namely, the skin film or the shoe upper skin film means a film comprising: a thermoplastic polyurethane film or polyurethane skin having formed thereon a printed layer which is formed by a conventional printing method proposed in the present invention and which has various colors and patterns; and a thermoplastic polyurethane hot-melt film disposed under the thermoplastic polyurethane film or polyurethane skin. In this regard, the polyurethane skin refers to one which is generally dry-coated on the hot-melt film, and the thermoplastic polyurethane film refers to one which is generally coextruded with the hot-melt film by a T-die extruder.

The present invention is intended to provide a shoe upper skin film for preventing dye migration, which comprises: a polyurethane skin or thermoplastic polyurethane film (hereinafter referred to as “TPU film”) having a color layer; and a thermoplastic polyurethane hot-melt film (hereinafter referred to as “hot-melt film”), wherein a film formed of an ethylene-vinyl alcohol copolymer (hereinafter referred to as “EVOH”) is disposed between the TPU film and the hot-melt film so that the dye in a fabric can be prevented from migrating to the skin film when the skin film is bonded to the fabric, thereby preventing staining of the color layer of the skin film.

The present invention also provides a skin film for preventing dye migration, which comprises: a hot-melt film made from a mixture of a thermoplastic polyurethane and an EVOH resin; and a TPU film formed on the hot-melt film.

The skin film according to the present invention is generally made by two methods. Specifically, the skin film is preferably made using a conventional T-die extruder or made by sequentially coating a dye migration-preventing film formed of EVOH resin and a TPU film on a hot-melt film by a dry coating method.

The dye migration-preventing film formed of EVOH resin in the inventive shoe upper skin film as described above can prevent the dye in a fabric from migrating to the skin film when the skin film is bonded to the fabric by a conventional heat press operation, thereby preventing the color layer from being stained. In addition, the EVOH resin contained in the hot-melt film of the skin film according to the present invention can prevent the dye in a fabric from migrating to the skin film during a heat press operation, thereby preventing the color layer from being stained.

Hereinafter, the present invention will be described in detail with reference to preferred examples, but the scope of the present invention is not limited by these examples.

Example 1

FIG. 3 is a figure showing the configuration of a shoe upper skin film for preventing color migration according to a preferred embodiment of the present invention. A skin film 100 according to the present invention is made by a co-extrusion method or a dry coating method. Specifically, the skin film 100 is made to have a three-layer structure and a total thickness of 0.10 to 0.50 mm.

Referring to FIG. 3, the skin film 100 according to the present invention comprises: a hot-melt film 400 made of thermoplastic polyurethane and forming the bottom layer of the skin film; a dye migration-preventing film 300 made of EVOH resin and formed on the hot-melt film 400; and a TPU film 200 formed on the dye migration-preventing film 300. The EVOH resin which is a copolymer of ethylene and vinyl alcohol is a resin having an excellent effect on the prevention of gas permeation. When the EVOH film that is the dye migration-preventing film 300 is formed between the hot-melt film 400 and the TPU film 200, as shown in FIG. 5, the dye migration-preventing film 300 can prevent the dye in a fabric 40 from migrating to the TPU film 200 of the skin film during a conventional heat press operation, thereby preventing the color layer of the skin film 100 from being stained. Namely, the dye migration-preventing film 300 made of EVOH resin functions as a film that prevents the skin film 100 from being stained by migration of a dye from the fabric.

Example 2

FIG. 4 is a figure showing the configuration of a shoe upper skin film for preventing color migration according to another preferred embodiment of the present invention. A skin film 500 according to the present invention is formed to have a two-layer structure and a thickness of 0.10 to 0.50 mm. It is made by a co-extrusion method using a conventional T-die extruder or made by forming a TPU film 200 on a hot-melt film 600 by a dry coating method.

Referring to FIG. 4, the skin film 500 according to the present invention is composed of a TPU film 200 and a hot-melt film 600. The TPU film 200 is made of thermoplastic polyurethane, and the hot-melt film 600 is made of a mixture of thermoplastic polyurethane and EVOH resin. Namely, to make the hot-melt film 600, a mixture of 5-95 wt % of thermoplastic polyurethane and 95-5 wt % of EVOH resin is preferably used

In the skin film 500 configured as described above, EVOH contained in the hot-melt film 600 can also prevent the dye in the fabric 40 from migrating to the TPU film 200 during a hot-melt operation, thereby preventing staining of the color layer of the skin film 500.

The shoe upper skin film according to the present invention is made by forming a dye migration-preventing film layer of EVOH resin between a TPU film and a hot-melt film or made by adding the EVOH resin to make a hot-melt film. Thus, the shoe upper skin film has an advantage in that the EVOH film can prevent the dye in a fabric from migrating to the skin film when the skin film is bonded to the fabric by a conventional heat press operation. For this reason, the skin film has advantages in that the color layer of the skin film can be prevented from being stained and in that the colors of the skin film having various patterns and colors can be maintained intact even when the shoe is used for a long period of time. 

What is claimed is:
 1. A shoe upper skin film for preventing dye migration, comprising: a hot-melt film; a dye migration-preventing film made of an ethylene-vinyl alcohol copolymer resin and formed on the hot-melt film; and a polyurethane film formed on the dye migration-preventing film.
 2. A shoe upper skin film for preventing dye migration, comprising: a dye migration-preventing hot-melt film made by processing a mixture of a thermoplastic polyurethane and an ethylene-vinyl alcohol copolymer; and a polyurethane film formed on the dye migration-preventing hot-melt film. 